Sonic drive for press fitting system

ABSTRACT

An elastic beam member is vibrationally driven by orbiting-mass oscillator means so as to set up a standing wave pattern therein. Means are provided to support the beam at points therealong where nodes of the standing wave appear. The beam is coupled to members to be press fitted together at one or more points therealong lying between the node and antinode of the standing wave pattern, this point being chosen to provide an optimum impedance match between the beam and such members. Means are provided to mechanically urge the members together, while sonic energy is simultaneously applied to the interface therebetween to implement the press fitting action.

United States Patent Bodine [54] SONIC DRIVE FOR PRESS FITTING SYSTEM [72] Inventor: Albert G. Bodine, 7877 Woodley Avenue,

Van Nuys, Calif. 91406 [22] Filed: Oct. 1, 1969 [21] Appl. No.: 862,905

Related US. Application Data [63] Continuation-impart of Ser. No. 423,771, Jan. 6, 1965, Pat. No. 3,581,027, which is a continuation of Ser. No. 756,382, Aug. 21, 1958, Pat. No. 3,169,589.

[52] US. Cl..... ..29/252 [51] Int. Cl ..B23p 19/04 [58] Field of Search ..29/525, 252, 255, 243.52, 243.53,

[ 1 May 30, 1972 3,245,138 4/1966 De Wilde ..29/525 X Primary ExaminerAndrew R. J uhasz Assistant Examiner-Leon Gilden Attorney-Sokolski & Wohlgemuth [57] ABSTRACT An elastic beam member is vibrationally driven by orbitingmass oscillator means so as to set up a standing wave pattern therein. Means are provided to support the beam at points therealong where nodes of the standing wave appear. The beam is coupled to members to be press fitted together at one or more points therealong lying between the node and antinode of the standing wave pattern, this point being chosen to provide an optimum impedance match between the beam and such members. Means are provided to mechanically urge the members together, while sonic energy is simultaneously applied to the interface therebetween to implement the press fitting action.

7 Claims, 12 Drawing Figures PATENTEDMAY 30 I972 3. 665.5 82

SHEET 1 BF 3 INVENTDR ALBERT G. mDlNE WSKI 8| WOl-iLGEMUTH FIG. I

ATTORNEYS PATENTEDMAY 30 I972 SHEET 2 BF 3 INVENTOR ALBERT G. KDINE 80((1SKI 8: \MHLGEMUTH ATTORNEYS PATENTEDMAYSOIBYZ 3,665,582

saw 3 BF 3 INVENTOR ALBERT G. BODINE SQOLSKI 8| WQ'ILGENIJTH ATTORNEYS SONIC DRIVE FOR PRESS FITTING SYSTEM This application is a continuation in part of my application Ser. No. 423,771, filed Jan. 6, I965, now U.S. Pat. No. 3,581,027 which in turn enjoys continuing status with my application Ser. No. 756,382 filed Aug. 21, I958 now US. Pat. No. 3,169,589.

In my aforementioned application Ser. No. 423,77l, a method and apparatus are described for sonic press fitting two members in which sonic energy is applied to the members to be fitted to facilitate their joinder. Particularly, in connection with FIGS. 7-11 of that application, apparatus is described for implementing sonic press fitting in which a standing wave pattern is set up in an elastic beam, the energy being coupled from such beam to the members being fitted while they are simultaneously being urged together. In this apparatus, the sonic beam is coupled to an adapter member at points therealong intermediate the positions on the beam where the nodes and antinodes of the standing wave pattern appear, the adapter being used to transfer the sonic energy to the members to be press fitted.

It has been found that the location of the coupling between the resonant beam and the adapter member at an optimum point between the node and antinode of the standing wave pattern affords significant improvement in operation enabling the design of the apparatus for optimum impedance matching of the sonic energy to the workpiece.

The instant invention is primarily concerned with the apparatus for such optimum coupling. Another aspect of this invention is the provision of hand operated apparatus for implementing such operation, incorporating a sonic rectifier which couples only unidirectional sonic energy to the workpiece, such unidirectional sonic action being solely in the direction in which the mechanically driven member is being urged. Such use of sonic rectification keeps the driving head more closely in contact with the workpiece and provides vibrational pulses solely in the driving direction, thus aiding the driving operation.

It is therefore the principal object of this invention to provide an improved apparatus for sonic press fitting wherein optimum impedance coupling of a resonant bar to the workpiece is achieved, and more efiective driving is obtained by sonic rectification of the resonant energy.

Other objects of the invention will become apparent as the description proceeds in connection with the accompanying.

drawings of which,

FIG. 1 is an elevational view in cross section of a first embodiment of the device of the invention;

FIG. 1A is a cross-sectional view taken along the plane indicated by IA-IA in FIG. 1,

FIG. 2 is a cross-sectional view taken along the plane indicated by 2-2 in FIG. 1,

FIG. 3 is a cross-sectional view taken along the plane indicated by 3-3 in FIG. 1.

FIG. 3A is a cross-sectional view taken along the plane indicated by 3A-3A in FIG. 3,

FIG. 4 is a fragmentary end view of the sonic vibratory beam as shown in FIGS. 13,

FIG. 4A is a fragmentary view of the middle portion of the sonic beam shown in FIGS. l-3,7 illustrating the work parts after they have been driven together,

FIG. 5 is a cross-sectional view taken along the plane indicated by 5-5 in FIG. 4,

FIG 6 is an elevational view of a second embodiment of the device of the invention,

FIG. 6A is a cross-sectional view taken along the plane indicated by 6A-6A in FIG. 6,

FIG. 6B is a cross-sectional view taken along the plane indicated by 6B -6B in FIG. 6,and

FIG. 7 is a top plan view of the embodiment of FIG 6.

Briefly described, the apparatus of the invention comprises an elastic beam which is resonantly vibrated in response to an orbiting-mass oscillator sonic generator to set up a standing wave pattern therein. Means are provided to couple the sonic beam to members to be press fitted together at points along the beam between the positions of the standing wave nodes and antinodes, this position being chosen to afford optimum impedance matching of the energy to the workpiece. The beam is supported from a support member at the points therealong where the standing wave nodes are located so that a minimal amount of sonic energy is transferred to the support. Means are further provided to urge the sonic beam against a member to be press fitted while the sonic energy is simultaneously applied to implement the efficient fitting of the members. In one embodiment thereof, sonic rectification of the sonic energy is provided so that only one direction of the sonic vibratory oscillation is transferred from the sonic beam to the workpiece, thereby more effectively utilizing the sonic energy to implement the urging of the members to their final press-fit relationship.

, It has been found most helpful in analyzing this invention to analogize the acoustically vibrating circuit utilized to an equivalent electrical circuit. This sort of approach to analysis is well known to those skilled in the art and is described, for

example, in Chapter 2 of Sonics by I-Iueter and Bolt,

published in 1955 by John Wiley and Sons. In making such an analogy, force F is equated with electrical voltage E, velocity of vibration u is equated with electrical current i, mechanical compliance C,, is equated with electrical capacitance C mass M is equated with electrical inductance L, mechanical resistance (friction) R,, is equated with electrical resistance R and mechanical impedance Z,,. is equated with electrical impedance 2,.

Thus, it can be shown that if a member is elastically vibrated by means of an acoustical sinusoidal force F, sinwt-(w being equal to 21r times the frequency of vibration, that Where 10M is equal to (l/wC a resonant condition exists, and the effective mechanical impedance 2,, is equal to the mechanical resistance R,,,, the reactive impedance components (0M and (l/wC a resonant condition exists, and the effective mechanical'impedance Z,, is equal to the mechanical resistance R,,,, the reactive impedance components mM and (I/wCm) cancelling each other out. Under such a resonant condition, velocity of vibration u is at a maximum. PQwer factor is unity, and energy is more efficiently delivered to a load to which the resonant system may be coupled.

It is important to note the significance of the attainment of the attainment of high acoustical Q in the resonant system being driven, to increase the efficiency of the vibration thereof and to provide a maximum amount of power. As for an equivalent electrical circuit, the Q of an acoustically vibrating circuit is defined as the sharpness of resonance hereof and is indicative of the ratio of the energy stored in each vibration cycle to the energy used in each such cycle. 0" is mathematically equated to the ratio between (0M and R,,,. Thus, the effective "Q" of the vibrating circuit can be maximized to make for highly efficient, high-amplitude vibration by minimizing the effect of friction in the circuit and/or maximizing the effect of mass in such circuit.

In considering the significance of the parameters described in connection with equation I it should be kept in mind that the total effective resistance, mass, and compliance in the acoustically vibrating circuit are represented in the equation and that these parameters may be distributed throughout the system rather than being lumped in any one component or portion thereof.

It is also to be noted that orbiting-mass oscillators are utilized in the implementation of the invention that automatically adjust their output frequency and phase to maintain resonance with changes in the characteristics of the load. Thus, in the face of changes in the effective mass and compliance presented by the load with changes in the conditions of the work material as it is sonically excited, the system automatically is maintained in optimum resonant operation by virtue of the "lock-in" characteristic of applicant's unique orbitingmass oscillators. Furthermore in this connection the orbitingmass oscillator automatically changes not only its frequency but its phase angle and therefore its power factor with changes in the resistive impedance load, to assure optimum efficiency of operation at all times. The vibrational output from such orbiting-mass oscillators also tends to be constrained by the resonator to be generated along a controlled predetermined coherent path to provide maximum output along a desired axis.

Referring now to FIGS. 1-5, a first embodiment of the device of the invention is illustrated. This embodiment will be described but briefly in view of the thorough description thereof contained in my application Ser. No. 423,771, of which the instant application is a continuation in part. Beam member 1 1 has orbiting-mass oscillators 12a and 12b mounted in the opposite ends thereof. Theseoscillators, as shown in FIGS 4 and 5, comprise a rotor 17 in the form of a ring which is supported on a central post 18, the ring having a greater inside diameter than the outside diameter of the post. Post 18 is in the form of a hollow cylinder and has apertures 18a formed in the walls thereof. An air jet as indicated by arrows 20 is fed to the center of post 18 from pneumatic line 22, this air jet impinging against the inner circumference of ring 17, thereby giving it its rotational drive. Oscillators of this type are described in my US. Pat. No. 2,960,314.

The rotor of oscillator 12a is driven in a clockwise direction, while that of oscillator 12b is driven counterclockwise, both such rotors being driven at the same speed, the eccentric rotation of the rotors about their associated posts developing vibrational energy which is transferred to beam 11. In view of the opposite rotation of the two rotors, the vibrational components along the longitudinal axis of the beam tend to cancel each other out, with the transverse vibrational components reinforcing each other, thereby resulting in a resultant vibration in the thickness plane of the beam, as indicated by arrows 25. The speed of rotation of oscillators 12a and 12b is adjusted to provide a vibration frequency which will set up a resonant standing wave pattern in beam 11, as indicated by graph lines 30.

Beam 11 is supported from platen 31 by means of ears 31a and 31b which subtend from the platen and are fixedly pinned to the beam. Platen 31 in turn is resiliently supported on frame 38 by means of rods 41 which are threadably attached to the platen and which are slidably supported in associated brackets 43, which are fixedly attached to frame 38. The resilient sup port is provided by means of springs 44 which are located between the head portions 41a of the rods and the tops of end portions 43a of the brackets, the springs thus urging rods 41 upwardly and thereby urging platen 31 against the bottom surfaces of the end portions 43a of the brackets.

Adapter member 50 is attached to beam 11 at points therealong which are between the nodal points 300 of the standing wave and the antinode b point of maximum amplitude of vibration. Such attachment is achieved by means of attachment ears 51 which extend from adapter member 50 and are fixedly pinned to the beam. The exact points of attachment are chosen so as to provide optimum impedance matching of the sonic energy from the beam through the adapter to the workpiece, thereby assuring maximum transfer of sonic energy for aiding the press fitting operation. Adapter member 50 rests against the surface of member 55 which is to be press fitted into member 57.

Platen 31 and along with it bar member 11 and adapter 50 are urged downwardly by means of hydraulic ram 60, which is driven downwardly against the platen by drive means (not shown). While such driving action is taking place, beam 11 is simultaneously being resonantly vibrated with a standing wave vibration pattern so as to facilitate the driving action and to readily enable the tight fitting of the parts as shown in FIG. 4A. The optimum utilization of the sonic energy to this end result is greatly enhanced by virtue of the optimum impedance matching between beam 11 and the load including adapter 50 and the workpiece. This end result, as already noted, is achieved by connecting the adapter to a point along the beam between the standing wave nodes and antinodes at which the desired optimum impedance match is achieved, this positioning being made in optimum fashion for each particular design.

As shown in FIGS 3 and 3A, and as fully described in my aforementioned application Ser. No. 423,77l, an additional resonant bar member 111 may be supported from frame 38 in similar fashion to the bar just described, and may be urged against the workpiece by means of a ram 160 to provide sonic energy to member 57 to further facilitate the press fitting of member 55 therein. As for the first sonic bar member, this member should be attached to its associated adapter 150 by means of ears 151 at points on the standing wave pattern whereat optimum impedance matching is achieved.

Referring now to FIGS. 6, 6A, 6B and 7, a second embodiment of the device of the'invention is illustrated. The same numerals are utilized in these Figures to identify the corresponding components shown in the embodiment of FIGS L5. This second embodiment differs from the first in that it is a hand tool, manual pressure being applied rather than the application of pressure by a hydraulic ram, and in the use of means for rectifying the sonic energy applied to the workpiece.

As for the first embodiment, elastic beam member 11 has a pair of orbiting-mass oscillators 12a and 12b mounted in the ends thereof, these oscillators being rotated in opposite directions at a speed such as to set up resonant standing at ave vibration in the beam, as indicated by graph line 30. Bar member 70 is attached to elastic beam 1 l at points therealong where the nodes 300 of the standing wave pattern appear. Handle bars 72 and 73 for the use of the operator in applying force against the workpiece are attached to bar member 70 by means of bolts 75.

Adapter member 50 for use in driving member 55 into member 57 is attached to sonic beam 11 by means of pins 80, which are swaged to the beam and which fit loosely into oversize apertures 82 formed in ear portions 51 which protrude from adapter 50. A spring 85 is located between adapter 50 and beam 11 directly below each of pins and acts to urge beam 11 upwardly with the pins 80 abutting against the top portions of the apertures formed in ears 51, as shown in FIG. 6B.

The device is operated by pressing downwardly on the handles 72 and 73 to apply force against member 55 which is to be press fitted into member 57, while simultaneously energizing sonic beam 11 with a resonant standing wave pattern as indicated by graph line 30. In response to the downwardly applied hand pressure, spring are compressed until pins 80 abut against the bottoms of apertured portions 82 of ears 5]. With pin 80 in this downward position, only the downward vibratory excursions will be transferred therethrough to drive adapter 50, the pin moving away from its intimate contact with the ear portions during the upward vibratory excursions. In this manner, an effective sonic rectification is achieved whereby only downward pulses of energy are applied from adapter 50 to member 55. The use of such sonic rectification in the device of the invention tends to improve the driving action by keeping the drive adapter in better contact with the workpiece and eliminating sonic amplitude components directed opposite to the direction of drive.

The device of this invention thus provides apparatus for more efficiently press fitting two members together, utilizing sonic energy to facilitate the press fitting action.

lclaim:

1. Apparatus for press fitting two members together comprising an elastic beam member, sonic oscillator means for resonantly vibrating said beam member so as to set up a standing wave therein, said standing wave having at least one node and one antinode,

driving adapter means attached to said resonant beam member therealong intermediate the node and antinode of the standing wave, said intermediate point being one providing optimum impedance matching of the sonic energy to said members and means for driving said drive adapter against one of said members to force fit it into the other of said members.

2. The device of claim 1 further including means for supporting said elastic beam, said support means being attached to said beam at nodal points of said standing wave, said adapter means being fixedly attached to said beam at two points therealong intermediate the node and antinode of the standing wave.

3. The device of claim 1 wherein said means for connecting said sonic beam to said drive adapter includes sonic rectifier means for coupling sonic energy to said drive adapter only in the direction of the driving action.

4. The device of claim 3 wherein said sonic rectifier means includes ear members protruding from said driving adapter, pin means fixedly attached to said beam, said ear members having apertures therein for receiving said pin member in a loose fit, and spring means interposed between said beam and said driving adapter to urge these members apart.

5. The device of claim 1 wherein said driving means comprises a platen attached to said beam at standing wave nodal points therealong and a hydraulic ram for driving said platen.

6. The device of claim 1 wherein said driving means comprises a bar member attached to said beam at standing wave nodal points therealong and handle means attached to said bar member.

7. The device of claim 1 and further including a second resonant beam member and second sonic oscillator means for setting up standing wave vibration in said second beam member, second driving adapter means attached to said second beam member therealong between the node and antinode of the standing wave for optimum impedance matching, and means for driving said second driving adapter against the other of said members. 

1. Apparatus for press fitting two members together comprising an elastic beam member, sonic oscillator means for resonantly vibrating said beam member so as to set up a standing wave therein, said standing wave having at least one node and one antinode, driving adapter means attached to said resonant beam member therealong intermediate the node and antinode of the standing wave, said intermediate point being one providing optimum impedance matching of the sonic energy to said members and means for driving said drive adapter against one of said members to force fit it into the other of said members.
 2. The device of claim 1 further including means for supporting said elastic beam, said support means being attached to said beam at nodal points of said standing wave, said adapter means being fixedly attached to said beam at two points therealong intermediate the node and antinode of the standing wave.
 3. The device of claim 1 wherein said means for connecting said sonic beam to said drive adapter includes sonic rectifier means for coupling sonic energy to said drive adapter only in the direction of the driving action.
 4. The device of claim 3 wherein said sonic rectifier means includes ear members protruding from said driving adapter, pin means fixedly attached to said beam, said ear members having apertures therein for receiving said pin member in a loose fit, and spring means interposed between said beam and said driving adapter to urge these members apart.
 5. The device of claim 1 wherein said driving means comprises a platen attached to said beam at standing wave nodal points therealong and a hydraulic ram for driving said platen.
 6. The device of claim 1 wherein said driving means comprises a bar member attached to said beam at standing wave nodal points therealong and handle means attached to said bar member.
 7. The device of claim 1 and further including a second resonant beam member and second sonic oscillator means for setting up standing wave vibration in said second beam member, second driving adapter means attached to said second beam member therealong between the node and antinode of the standing wave for optimum impedance matching, and means for driving said second driving adapter against the other of said members. 